The present invention relates to a board cleaning apparatus and a board transporting apparatus, for removing foreign matter such as dust, dirt and other adherents from a surface of a circuit board in a circuit board transporting process.
In general, electrode terminals and circuits are printed on one side or both sides of a circuit board. Then, an adhesive layer is printed on the circuit board and components are mounted on the circuit board. Further, the circuit board is subjected to electrical connection by soldering reflow; thus, a product is obtained. During these processes, foreign matter tends to adhere to the surface of the circuit board upon processing and in the middle of the transporting process, and might cause an issue with the product. In order to improve this issue, a process of removing foreign matter from the circuit board is generally carried out at an appropriate stage in the middle of the processing and transporting processes.
Conventionally, the foreign-matter removing process has been carried out through processes, such as air blowing onto the surface of the circuit board, pressing a fixed brush thereon, pressing a sticky roller thereon and a manual operation using a cloth; however, these processes do not necessarily provide the desired results. For example, in the case where foreign matter firmly sticks to the surface of the circuit board due to moisture and scattered adhesive or the like, the air blowing process fails to remove the foreign matter. Moreover, the pressing of a fixed brush thereon fails to sufficiently remove the foreign matters although a static-eliminating effect is obtained, and, in the case where the foreign matter overlaps each other, the pressing of a sticky roller tends to cause some of the foreign matter to be left on the circuit board, and also requires time-consuming replacing processes after the use of a predetermined amount of the sticky roller.
In the conventional art, a technique has been proposed in which an air blower, an air aspirator, a rotary brush and transporting rollers are housed in a semi-cylindrical shaped container using a bellows or the like, and the containers are placed on both of the faces of the circuit board to completely cover the circuit board from both of the sides so that foreign matters are removed therein (for example, see Japanese Unexamined Patent Publication No. H02-50822). However, the apparatus of this type becomes bulky, and it is difficult to attach the apparatus to a limited space back or front the processing apparatus, or in the transporting apparatus for the circuit board.
In order to improve these issues, in the conventional art also, a board cleaning apparatus for a circuit board, which has a small size and is easily attached, has been proposed. FIGS. 5A and 5B show the outline of the board cleaning apparatus structure. FIG. 5A is a perspective view showing a board transporting apparatus equipped with the board cleaning apparatus 50, and FIG. 5B is a cross-sectional view of the board cleaning apparatus 50 taken along the XZ-plane of FIG. 5A. In FIGS. SA and 5B, the board cleaning apparatus 50 is provided with a case 51, a rotary brush 52 installed in the case 51, a motor 153,for driving a rotation of the rotary brush 52 and a cylindrical duct 54 that sucks foreign matters by introducing negative-pressure air to the board cleaning apparatus 50. The duct 54 is connected to a negative-pressure supply source 160 installed outside the case 51 through a hose 156.
A circuit board 1 (numeral 1a indicated by a solid line or numeral 1b indicated by a broken line in FIG. 5A) is transported while being supported by a pair of opposing board transporting rails 2 (2a and 2b). Each of the board transporting rails 2a and 2b has a virtually U-shaped cross section with a concave section provided in a center portion thereof, and conveyor belts, not shown, are housed inside the concave section. The circuit board 1 is inserted into the concave section in the U-shaped cross section of the two board transporting rails 2a and 2b, and placed on the conveyor belts to be transported in the X-direction of FIG. 5A (the board transporting direction “S” in FIG. 5B).
When the board cleaning apparatus 50 having the above-mentioned structure is operated, the rotary brush 52 (see FIG. 1B), which has been made face to face with the circuit board 1 transported by the paired board transporting rails 2, is allowed to rotate in a direction indicated by an arrow A to brush the surface of the circuit board 1 so that foreign matters that adhere to the surface of the circuit board 1 are wiped off and ejected by the rotary brush 52. A suction force is exerted in the duct 54 connected to the negative-pressure supply source 160 through the hose 156 so that the foreign matters, removed and ejected by the rotary brush 52 to float in the case 51, are sucked into the duct 54 as indicated by an arrow B through a function of the negative-pressure air from the negative-pressure supply source 160 and removed.